Ever since the advent of tall buildings and structures in which many people live, work or visit, it has been a safety concern to safely facilitate escape/rescue of such people in emergency situations. Emergency escape may be needed in a variety of situations such as earthquakes, fire, and terror attacks—especially from higher levels of structures where ladders or other conventional rescue equipment do not conveniently reach and when rescue personnel simply cannot respond quickly enough.
A variety of devices are known in the crowed art of equipment for emergency descent. Among the many known devices, a variety makes use of equipment for gliding about a cable. These generally incorporate a descent mechanism comprising a rope (or cable) wound around a spool or drum a rope threaded through a pulley system or a rope or strap snaking through a plurality of rods, thereby imparting friction and retarding the rate of descent or facilitating the control of descent rate.
The devices further incorporate, or are designed for use with, harnesses—having a means of attaching the harness to the decent mechanism—and an anchoring means.
The disclosures in U.S. Pat. No. 5,379,858 to Sandoval; U.S. Pat. No. 5,145,036 to Omaha; U.S. Pat. No. 4,550,801 to Forrest; and U.S. Pat. No. 503,971 to Jewell illustrate examples of more closely related prior art due the geometry of their descent mechanisms or the descent characteristics as a result of the design.
U.S. Pat. No. 5,379,858 describes a descender system comprising an elongated strap channeled through a descent mechanism having five parallel cylindrical pins supported side-by-side. The strap is serpentinely channeled through an upper set of three adjacent pins; the fourth pin is used to provide friction on the strap for controlling the rate of descent via pressure from a rotatable knob; and the fifth pin secures a harness to the descent mechanism.
U.S. Pat. No. 5,145,036 discloses a descent-retarding device comprising a U-shaped steel frame with five cross bars. Two of the crossbars can be swung open to facilitate reeving a rope over and under the bars. Springs coiled around arms of the U-shaped steel frame provide compression on the rope and crossbars to provide friction and slow the sliding of the rope. The lowest cross bar, adjacent the springs, is long enough to be grasped and can be pulled down to reduce the spring compression on the rods and rope thereby increasing the rate of descent. When this cross bar is completely released, the springs expand to bring the user to a complete stop.
However, both of the above-mentioned patents disclose descending systems that require user input to control the descent. Such devices could prove useless to a user who is likely to be anxious, confused or may even lose consciousness during descent, due to the stress of an emergency that would require the use of such a device.
U.S. Pat. No. 4,550,801 discloses a device that overcomes the above-mentioned issues with an apparatus including a load-lowering device in the form of a small cylindrical drum or spool. Rope is wound around the spool to provide friction and is also threaded through apertures in the upper and lower ends of the spool. The lower aperture has tapered slits on either side and due to the clockwise (or counterclockwise) rotation of the rope on the spool, there is a tendency for the rope to be biased toward one of either of the tapered slits thereby providing more friction and slowing descent. If the user is alert, he or she may press on the rope to remove it from the slit and thereby increase the rate of descent. However, the use of the hands may result in rope burn or the user's hand could get caught between the rope and the mechanism causing pain or, even worse, possibly stopping descent to safety.
In the crowded art, there are other disclosures of safety devices for descending from heights that do not require the user to control descent speed, however these devices typically suffer from one or more of the following issues including: complicated mechanisms, bulky mechanisms, intricate rope/strap threading or reeving patterns allowing problems such as abrading or tangling, unstable harnesses (sometimes requiring a user to hang on to a component in order to maintain stability), harnesses that are complicated or difficult to don, etc.
Furthermore, none of the prior art descender systems incorporate a means of protecting a user descending from a building or tall structure from receiving blows from items such as the outer wall of the building or its ledges, etc.